Substrate treating method and production method for semiconductor device

ABSTRACT

A method of hydrogen sintering a substrate including a semiconductor device formed thereon comprises the steps of exciting a processing gas comprising a noble gas and a hydrogen gas to form a plasma comprising hydrogen radicals and hydrogen ions, and exposing the substrate to the plasma. A preferred method comprises forming a gate insulation film on a substrate, forming a polysilicon electrode on the gate insulation film, and exposing the polysilicon electrode to an atmosphere comprising hydrogen radicals and hydrogen ions.

TECHNICAL FIELD

The present invention generally relates to fabrication of electronicdevices, and more particularly, to a substrate processing method inwhich a substrate for an electronic device on which substrate asemiconductor device is formed is exposed to hydrogen radicals.

BACKGROUND ART

In the fabrication process of a semiconductor device, it isindispensable to perform a hydrogen sintering process which performsthermal processing on a substrate for an electronic device on whichsubstrate various semiconductor devices are formed in a hydrogenatmosphere. By performing such a hydrogen sintering process, in a MOSFET(Metal-Oxide-Semiconductor Field Effect Transistor), for example,dangling bonds at the interface region between a channel substrate and agate insulation film are terminated with hydrogen radicals, anddegradation of the electric properties of the semiconductor devicescaused by capturing of electric charges by the dangling bonds issuppressed.

There are various semiconductor devices that use a hydrogen sinteringprocess. Specific examples of such semiconductor devices are: a logicaldevice that requires a high-speed operation; a memory device representedby DRAM using a high dielectric constant material (High-k) as aninterelectrode insulating film; and a TFT (Thin Film Transistor) formedon a glass substrate. A description is given below of the reason thesemiconductor devices require a hydrogen sintering process.

On the other hand, a high dielectric constant material (High-k) such asTa₂O₅ is used as an interelectrode insulating film used for a memorycell of DRAM. However, when a semiconductor device including such a highdielectric constant material is processed (e.g., etching or a hydrogensintering process) under a condition where a large quantity of hydrogenradicals exist, degradation of characteristics such as an increase inleakage current and a reduction of dielectric constant tend to occur(refer to Atsuhiro Tsukune, “Cu Damascene Formation Process”, The 8thsemiconductor process symposium, Sep. 20, 1999, pp. 71–79).

In addition, since a TFT is formed on a glass substrate, it is essentialto perform a process at low temperature of 400° C. or less. However, itis difficult to form an oxide film having good characteristics in such atemperature region by thermal oxidation. Thus, at present, an oxide filmformed by CVD or plasma oxidation is used as a gate insulation film.However, the insulating property of the oxide film fabricated by suchmethods is significantly inferior to that of a thermal oxide film, and aproblem of an increase in energy consumption due to an increase ofleakage current occurs, which is disadvantageous for application to amobile terminal requiring low electric power consumption (refer to N.Sano, M. Sekiya, M. Hara, A. Kohno and T. Sameshima, “Improvement ofSiO₂/Si interface by low-temperature annealing in wet atmosphere”,Applied Physics Letters, volume 66, Number 16, 1995, pp. 2107–2109).

In order to improve the characteristics of such a gate insulation film,a hydrogen sintering process by thermal processing has been used.However, when forming hydrogen radicals by heat treating, hightemperature of 450° C. or more is required. Hence, application to a SiGesubstrate and a TFT, which require low temperature processing, isdifficult. Additionally, in a case where a hydrogen sintering process bythermal processing is used, hydrogen radicals are mainly controlled bytemperature. However, in formation of a semiconductor device in which aheat-resistant material (a material having high heat stability) and amaterial easily affected by heat (a material having low heat stability)are mixed, it is difficult to establish an optimum process. Further,though High-k materials used as an interelectrode insulation film of aDRAM are promising for the next generation gate insulation film, thematerials have a problem of, for example, an increase in the thicknessof an oxide film due to crystallization or reaction to silicon whensubjected to a high-temperature process after formation of the film.Hence, it is anticipated that it will be difficult to use a hydrogensintering process using heat on a semiconductor device mounting thereona High-k gate insulating film.

Wet annealing, which perform annealing in a H₂O atmosphere of about 300°C., has been proposed as a process covering the above-mentionedshortcomings (Sano et al., op cit., and D. Tchikatilov, Y. F. Yang andE. S. Yang, Appl. Phys. Lett. 69 (17) 21 Oct. 1996). However, since thetime period of annealing is about three hours, which is a long time, itseems that using wet annealing for mass production is difficult.

Therefore, a method using plasma, which can easily form and controlhydrogen radicals at a low temperature of 400° C., is drawing attentionas a most promising method for forming hydrogen radicals. There havealready been reported a large number of hydrogen radical formationsusing plasma. However, these plasma processes are techniques developedwith the aim of cleaning (Y. Aoki, S. Aoyama, H. Uetake, K. Morizuka andT. Ohmi, “In situ substrate surface cleaning by low-energy ionbombardment for high quality film formation”, J. Vac. Sci. Technol.A11(2), March/April 1993, pp. 307–313), and have problems of, forexample, plasma damage due to high electron temperature and difficultyin increasing the area processed.

On the other hand, recently, there has been proposed a plasma formationmethod, which uses a planar antenna and microwaves, as a plasmaprocessing method intended to form a gate insulation film.

In the method, a noble gas of, for example, He, Ne, Ar, Kr and Xe issupplied together with a gas including oxygen or nitrogen via a ringshower plate provided above a substrate to be processed to the spacebetween the substrate to be processes and the shower plate. By emittingmicrowaves from behind a planar antenna member (slot plane antenna; SPA)provided above the shower plate, the microwaves are propagated via theantenna. A technique has been proposed in which a noble gas isplasma-excited in the above-mentioned space by using the microwaves, andat the same time, radicals of a gas including oxygen or a gas includingnitrogen, for example, oxygen radicals O* or nitrogen radicals N*, areformed, thereby oxidizing or nitriding a surface of a silicon substrate.

Since the electron density of the plasma formed by this method is high,a large volume of radicals is formed even at a low substrate processingtemperature. In addition, since the electron temperature is low, plasmadamage, which becomes a problem in other plasma formation methods, islow. Further, since the microwaves propagated via the planar antennauniformly form plasma in a large area, it is reported that goodapplication is obtained with respect to a substrate having a large areasuch as a wafer having a diameter of 300 mm and a TFT display apparatussubstrate (Katsuyuki Sekine, Yuji Saito, Masaki Hirayama and TadahiroOhmi, J. Vac. Sci. Technol. A17(5), September/October 1999, pp.3129–3133).

With the use of such a technique, it is possible to directly perform anoxidizing or nitriding process on a surface of a substrate forelectronic devices even at a low substrate temperature of 400° C. orless.

DISCLOSURE OF THE INVENTION

Recently, aiming at high-speed logic devices, MOSFETs using as asubstrate a SiGe (Silicon Germanium) crystal film deposited on a Siwafer have been developed. Since the mobility of p-channels is increasedby using a SiGe crystal film as a channel layer, realization ofhigh-speed MOSFETs is expected.

When such a structure is used, it is necessary to form an oxide film ona SiGe crystal film as a gate insulating film. However, formation of agate oxide film by thermal oxidation causes formation of a mixed layerof SiO₂ and GeO₂, which results in degradation of the insulatingproperty compared to a pure SiO₂ film. Thus, formation of an oxide filmby CVD (Chemical Vapor Deposition), which allows formation of an oxidefilm at low temperature, and by plasma oxidation has been attempted. Theinsulating property of the oxide films thus formed is superior to thatof the mixed layer of SiO₂ and GeO₂, but the insulating property thereofis inferior compared to that of a pure thermal oxide film. For thisreason, operating characteristics that can be put into practical use arenot obtained (refer to T. Ngal, X. Chen, J. Chen, S. K. Banerjee,“Improving SiO₂/SiGe interface of SiGe p-metal-oxide-siliconfield-effect transistors using water vapor annealing”, Applied PhysicsLetters, vol. 80, Number 10, 2002, pp. 1773–1775).

Accordingly, a general object of the present invention is to provide anovel and useful substrate processing method in which the problemsdescribed above are eliminated.

A more specific object of the present invention is to provide a methodof processing with hydrogen radicals (including hydrogen ions) asubstrate for an electronic device represented by, for example, a Sisubstrate, a SiGe substrate, and a glass substrate, wherein formation ofhydrogen radicals is effectively controlled with a control method usingother than temperature, for example, pressure or gas flow rate.

Still another object of the present invention is to provide a substrateprocessing method capable of performing a hydrogen sintering process ata low substrate processing temperature on a substrate for an electronicdevice, on which substrate a semiconductor element is formed, withoutdamaging the substrate.

A further object of the present invention is to provide a substrateprocessing method capable of performing a hydrogen sintering process ata low substrate processing temperature on a substrate for an electronicdevice on which substrate a semiconductor device is formed, wherein themethod is particularly preferably used for a SiGe substrate or a glasssubstrate whose characteristics are significantly degraded by heat.

A still further object of the present invention is to provide asubstrate processing method capable of performing a hydrogen sinteringprocess at a low substrate processing temperature on a substrate for anelectronic device on which substrate a semiconductor device is formed,wherein the method is particularly preferably used for a semiconductordevice such as a DRAM including as an interelectrode insulation film aHigh-k material that requires control of hydrogen radical generation bya method using other than heat and a next generation logic deviceincluding as a gate insulation film in a MOSFET a High-k material.

Another object of the present invention is to provide a fabricationmethod of a semiconductor device including a gate insulation film formedat low substrate temperature by, for example, a thermal CVD method, aplasma method, and a hot wire method, wherein dangling bonds that existbetween a gate insulation film and a substrate, in the vicinity of theinterface between a gate insulation film and a gate electrode, or in thegate insulation film or the gate insulation film and a gate electrode,or in the gate insulation film or the gate electrode, are terminated byperforming a hydrogen sintering process at low substrate processingtemperature, thereby capable of compensating degradation in the electricproperties of the semiconductor device.

Another object of the present invention is to provide a substrateprocessing method that exposes to hydrogen radicals (including hydrogenions) a substrate for an electronic device on which substrate asemiconductor device is formed, wherein the hydrogen radicals areexcited by plasma.

Another object of the present invention is to provide a substrateprocessing method that exposes to hydrogen radicals (including hydrogenion) a substrate for an electronic device on which substrate asemiconductor device is formed, wherein the hydrogen radicals areexcited by microwave plasma.

Another object of the present invention is to provide a substrateprocessing method that exposes to hydrogen radicals (including hydrogenion) a substrate for an electronic device on which substrate asemiconductor device is formed, wherein the hydrogen radicals areexcited by plasma formed by emitting microwaves to a planar antenna(Slot Plane Antenna: SPA).

As can be appreciated, the technique may be applied to theabove-mentioned low temperature oxide film formation, and is alsopromising to be used as a hydrogen radical formation method aiming athydrogen sintering.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A through 1H show a fabrication process of an n-MOSFET as atypical application of a hydrogen sintering process according to thepresent invention;

FIG. 2 is a diagram showing the structure of a microwave plasmaprocessing apparatus used in the present invention;

FIG. 3 is a diagram for explaining a problem that occurs in thefabrication process of the semiconductor device of FIGS. 1A through 1H;

FIG. 4 is a diagram for explaining a first embodiment of the presentinvention;

FIG. 5 is another diagram for explaining the first embodiment of thepresent invention;

FIGS. 6A and 6B are diagrams for explaining a second embodiment of thepresent invention; and

FIG. 7 is a diagram showing a case where the present invention isapplied to a DRAM.

BEST MODE FOR CARRYING OUT THE INVENTION First Embodiment

FIGS. 1A through 1H show a fabrication process of an n-MOSFET as atypical application of a hydrogen sintering process according to thepresent invention. FIG. 2 shows one embodiment of a plasma formationapparatus using microwaves and a planar antenna, which apparatus is ahydrogen radical formation apparatus used in the present invention.

First, referring to FIG. 2, a microwave plasma processing apparatus 10includes a process chamber 11 provided with a substrate supporting table12, which supports a substrate W to be processed. The process chamber 11is evacuated via an exhaust port 11A.

An opening is formed in the process chamber 11 so as to correspond tothe substrate W on the substrate supporting table 12. The opening iscovered by a cover plate 13 made of a low-loss ceramic such as alumina.Further, a shower plate 14, which is made of a low-loss ceramic such asalumina and provided with a gas introducing path and a large number ofnozzle openings communicating with the gas introducing path, is formedunderneath the cover plate 13 so as to face the substrate W to beprocessed.

The cover plate 13 and the shower plate 14 form a microwave window. Amicrowave antenna 15 such as radial line slot antenna or a horn antennais formed outside the cover plate 14.

At the time of operation, the process space inside the process chamber11 is set to a predetermined processing pressure through evacuation viathe exhaust port 11A. In the plasma processing method aiming atformation of a gate insulation film, an inert gas of, for example, argonor Kr is introduced with a gas including oxygen from the shower plate14. Additionally, as is described below, in a plasma processing methodproposed in the present invention and aiming at formation of hydrogenradicals, a hydrogen gas is preferably used as a gas that is introducedwith the inert gas.

Further, microwaves having a frequency of several GHz are emitted from atop portion of the antenna 15. The emitted microwaves are propagatedthrough the antenna in a diameter direction, emitted to a bottom portionof the antenna, and introduced into the process chamber 11 by beingtransmitted through the cover plate 13. On this occasion, since themicrowaves are propagated via the antenna, plasma having high densityand low electron temperature is generated, and the plasma is uniformlydistributed in a wide region in proportion to the area of the antenna.Accordingly, with the use of the substrate processing apparatus of FIG.2, it is possible to process a large area such as a wafer having adiameter of 300 mm and a large TFT display substrate. Also, since theelectron temperature of the plasma is low, it is possible to preventdamage to the substrate W to be processed and an inner wall of theprocess chamber 11. Further, since the formed radicals flow in thediameter directions along the surface of the substrate W to be processedand are immediately exhausted, recombination of the radicals issuppressed and it is possible to perform an efficient and very uniformsubstrate process at a low temperature of 600° C. or less.

Next, referring to FIGS. 1A through 1H, in the process of FIG. 1A, ap-type silicon substrate 21 having (100) surface orientation and aresistivity of 1–30 Ωcm is used as a substrate. A device isolationstructure 21S is formed on the silicon substrate 21 by the STI or LOCOSprocess. Further, channel doping by boron is performed in a deviceregion 21C defined by the device isolation structure 21S. In the processof FIG. 1A, a sacrificial oxide film 20 is formed on a surface of thesilicon substrate 21 as a preliminary process for a gate insulation filmformation process, which is to be performed later.

Next, in the process of FIG. 1B, RCA cleaning, combining an APM (mixtureof ammonia, hydrogen peroxide, and deionized water), an HPM (mixture ofhydrochloric acid, hydrogen peroxide, and deionized water), and a DHF(mixture of hydrofluoric acid and deionized water), is used to performcleaning before gate insulation film formation with respect to thestructure of FIG. 1A. Thereby, the sacrificial oxide film 20 is removedtogether with contaminants such as metals, organic matter, andparticles, and a fresh surface of the silicon substrate 21 is exposed.In this process, according to need, a SPM (mixture of sulfuric acid andhydrogen peroxide), ozone water, an FPM (mixture of hydrofluoric acid,hydrogen peroxide, and deionized water), hydrochloric acid water(mixture of hydrochloric acid and deionized water), and organic alkali,for example, may be used.

Next, in the process of FIG. 1C, a gate oxide film 22 is formed on thesurface of the silicon substrate 21. For example, by performing anoxidizing process on the substrate subjected to the RCA cleaning shownin FIG. 1B for two minutes in an atmosphere having a pressure of 700 Paand a H₂/O₂ gas flow ratio of 100/700 SCCM while maintaining thetemperature of the substrate at 850° C., a thermal oxide film having athickness of about 2 nm is formed as the gate oxide film 22.

Next, in the process of FIG. 1D, a polysilicon film 23, which forms agate electrode, is deposited by CVD method on the gate oxide film 22 ofFIG. 1C. For example, by introducing a silane gas under a pressure of 30Pa while maintaining the temperature of the silicon substrate 21, havingthe gate oxide film 22 formed thereon, at 620° C., the polysilicon film23 is formed on the gate oxide film 22 with a thickness of 150 nm.

Then, in the process of FIG. 1E, by patterning the polysilicon film 23by a resist process, a gate electrode pattern 23A and a gate oxide filmpattern 22A are formed on the silicon substrate 21. Further, in the stepof FIG. 1F, by performing ion implantation of a p-type impurity elementsuch as As or P into the device region 21C, and subsequently performingactivation of the implanted ion by thermal processing, n-type diffusionregions 21A and 21B, which serve as a source region and a drain region,are formed in the silicon substrate 21 on both sides of the gateelectrode 23A.

Further, in the step of FIG. 1G, an interlayer insulation film 24, whichis formed by a low dielectric constant film such as TEOS, is formed onthe structure of FIG. 1F so as to cover the gate electrode 23A.Additionally, contact holes exposing the diffusion regions 21A and 21Band the gate electrode 23A are formed in the interlayer insulation film23 by selective etching. In addition, by filling the contact holes withan electrode material, which is indicated by oblique lines, a desiredMOSFET is obtained.

Incidentally, when forming the MOSFET of FIG. 1G, plasma processing isused in selective etching and an ashing process used in a resistremoving process. However, such plasma processing may cause degradationin the characteristics of a MOSFET in the vicinity of the interfacebetween the gate oxide film 22 and the silicon substrate 21 such as anincrease of the interface state. Hence, in a conventional fabricationprocess of a semiconductor device, a hydrogen sintering process isperformed on the obtained semiconductor structure shown in FIG. 1G.

FIG. 3 shows the C-V characteristics of a nMOS capacitor having astructure similar to that of FIG. 1E. It should be noted that, in FIG.3, the vertical axis represents the capacitance of the nMOS capacitorformed by the p-type silicon substrate 21, the gate oxide film 22, andthe n-type polysilicon gate electrode 23A, and the horizontal axisrepresents the gate voltage applied to the polysilicon gate electrode23A. It should be noted that, in the example shown in FIG. 3, theanalysis was made by using two-frequency analysis, which uses measuringfrequencies of 100 kHz and 250 kHz, with the area of the gate oxide film22 being 100 μm² (Akio Nara, Naoki Yasuda, Hideki Satake and AkiraToriumi, “A Guidance for Accurate Two-Frequency Capacitance Measurementfor Ultra-Thin Gate Oxide”, Extended Abstracts of Solid State Devicesand Materials, 2000, pp. 452–453).

Referring to FIG. 3, in a case where the hydrogen sintering processdescribed above is not performed, in a depletion region corresponding toa gate voltage of −0.5 V–+0.5 V, the existence of a large capacitancedue to the interface state is confirmed.

On the other hand, in a case where the hydrogen sintering process shownin FIG. 1H is performed by heating the structure of FIG. 1G to atemperature of 450° C. and leaving the structure in an atmosphere havinga H₂/N₂ ratio of 0.5% for 30 minutes, it can be seen that thecapacitance due to the interface state in the depletion region isreduced as shown in FIG. 3, and good C-V characteristics are obtained.

As mentioned above, in order to fabricate a MOSFET having good interfacecharacteristics, a hydrogen sintering process shown in FIG. 1H isindispensable. However, a conventional hydrogen sintering process byheat processing needs a high temperature of 400° C. or more, and it isbecoming difficult to preferably use a hydrogen sintering process byheat processing for fabrication of a TFT using a glass substrate and asemiconductor device such as a DRAM in which a material having superiorheat stability and a material having inferior heat stability are mixed.

FIG. 4 shows a hydrogen radical control method according to the firstembodiment of the present invention, using the substrate processingapparatus 10 of FIG. 2. It should be noted that, in FIG. 4, thehorizontal axis represents the processing pressure, and the verticalaxis represents the luminescence intensity of hydrogen radicals observedby OES (Optical Emission Spectroscopy). It should be noted that, in theexperiment of FIG. 4, the ratio of hydrogen gas supplied to the showerplate 14 of FIG. 2 with respect to Ar gas is 1%, and microwaves of 2.45GHz are emitted to the antenna 15 at a power of 2000 W.

Referring to FIG. 4, it can be seen that luminescence intensityequivalent to that in a case where a substrate temperature is 400° C. isobtained at a substrate temperature of 25° C., and it is possible togenerate enough hydrogen radicals even at low substrate temperature byforming hydrogen radicals with the use of the substrate processingapparatus 10 of FIG. 2. Additionally, it can be seen from FIG. 4 thatthe amount of the formed hydrogen radicals drastically varies bychanging the processing pressure. For example, it can be seen that, bychanging the processing pressure from 13.3 Pa (100 mTorr) to 267 Pa (2Torr), the luminescence intensity of hydrogen radicals is increased tofive times. This indicates a possibility that the generation amount ofhydrogen radicals can be controlled by a method other than conventionaltemperature control. Particularly, the relationship shown in FIG. 4Aindicates that, by controlling the processing pressure in the substrateprocessing apparatus 10, even at a low substrate temperature of 250° C.,the generation amount of hydrogen radicals can be controlled in a mannersimilar to that in the case where the substrate temperature is 400° C.and furthermore arbitrarily.

FIG. 5 shows the relationship between the electron temperature and theelectron density measured in the substrate processing apparatus 10 ofFIG. 2.

Referring to FIG. 5, it can be seen that, with the use of the substrateprocessing apparatus 10 of FIG. 2, it is possible to form plasma havingan electron temperature of 1.5 eV or less with an electron density of10¹¹ cm⁻³. This means that, according to the present invention, it ispossible to form a sufficient amount of hydrogen radicals under acondition where the electron temperature is lower than that in otherplasma formation methods, and thus with less plasma damage occurring.

As mentioned above, in the present invention, by forming plasma with theuse of the substrate processing apparatus 10 of FIG. 2 at the time offormation of hydrogen radicals, it is possible to control the electrontemperature of the formed plasma. Also, it is possible to prevent aproblem of damage to a semiconductor device caused by charged particles,which is considered to occur when other plasma formation methods areused.

In the present embodiment, the generation amount of hydrogen radicals iscontrolled by controlling the pressure. However, the generation amountof hydrogen radicals may be controlled also by varying the gas flow rateor the microwave power.

Additionally, in the present embodiment, it is also possible to generatehydrogen radicals by using an atmosphere including heavy nitrogen. Inthis case, heavy hydrogen radicals D* are formed in the atmosphere.

Further, the atmosphere including hydrogen radicals may include hydrogenions.

Second Embodiment

FIGS. 6A and 6B show a hydrogen sintering process according to oneembodiment of the present invention, using the substrate processingapparatus 10 of FIG. 2. It should be noted that those parts thatcorrespond to the above-described parts are designated by the samereference numerals, and a description thereof is omitted.

Referring to FIG. 6A, the silicon substrate 21 on which thesemiconductor device structure of FIG. 1G is formed is introduced intothe process chamber 11 of the substrate processing apparatus 10 as thesubstrate W to be processed. A mixed gas of a noble gas such as Ar or Krand hydrogen is introduced from the shower plate 14, and is excited withmicrowaves of 2.45 GHz or 8.3 GHz. Thereby, hydrogen radicals H* areformed.

For example, by reducing the processing pressure of the process chamber11 to 67 Pa, setting the substrate temperature to 250° C., and supplyinghydrogen gas and Ar gas into the process chamber 11 such that the ratioof H₂ becomes 1% (H₂/Ar=1%), an atmosphere including Ar plasma andhydrogen radicals H* is formed underneath the shower plate 14.

The hydrogen radicals H* thus formed easily enter the polysilicon gateelectrode 23A and terminate dangling bonds in the polysilicon gateelectrode 23A. Further, the hydrogen radicals H* thus formed passthrough the polysilicon film 23, reach inside the oxide film, theinterface between the polysilicon film and the oxynitride film, or theinterface between the oxide film and the silicon substrate, andterminate dangling bonds that exist in these regions, which danglingbonds are indicated by X. As a result, according to the presentinvention, similar to effects obtained by a hydrogen sintering processby heat, dangling bonds observed as a capacitance in the gate voltagerange of −5 V to +5 V are terminated, and the interface state densityassociated with such dangling bonds is decreased.

It should be noted that, also in the present embodiment, it is possibleto perform a restoring process of an interface by using heavy hydrogenradicals by supplying a mixed gas of hydrogen and heavy hydrogen orheavy hydrogen to the substrate processing apparatus 10 of FIG. 2.

In the present embodiment, the gate insulation film 22A of the MOSFET isformed by a thermal oxidation method. However, the gate insulation film22A may be formed by any of, for example, plasma oxidation, plasmanitriding, catalytic oxidation, catalytic nitriding, CVD (Chemical VaporDeposition), and PVD (Physical Vapor Deposition).

FIG. 7 shows a DRAM formed by applying a substrate processing method ofthe present invention. It should be noted that, in FIG. 7, those partsthat are described above are designated by the same reference numerals,and a description thereof is omitted.

Referring to FIG. 7, in the present embodiment, the gate electrode 23Aextends on the surface of the substrate 21 as a word line WL, and apolysilicon electrode pattern 26A, which is formed on the interlayerinsulation film 24 and forming a bit line BL, contacts the diffusionregion 21A, which forms a source region, via the contact hole formed inthe interlayer insulation film 24.

Additionally, another interlayer insulation film is formed on theinterlayer insulating film 24 so as to cover the bit line pattern 26A. Apolysilicon electrode pattern, which forms a storage electrode 26B of amemory cell capacitor, is formed on the interlayer insulation film 24such that the polysilicon electrode pattern contacts the diffusionregion 21B via a contact hole formed to penetrate the interlayerinsulation films 24 and 25.

A surface of the storage electrode 26B is covered with a high dielectriccapacitor insulation film 27. In addition, an opposing electrode 28 isformed on the interlayer insulation film 25 so as to cover the capacitorinsulation film 27.

Also in the DRAM of FIG. 7, similar to FIG. 6B, it is possible toterminate with hydrogen radicals H* the dangling bonds that exist in thevicinity of the interface between the silicon substrate 21 and the gateinsulation film 22A, inside the gate insulation film 22A or thepolysilicon electrode 23A, or in the vicinity of the interface betweenthe gate insulation film 22A and the polysilicon electrode 23A by plasmaprocessing by the substrate processing apparatus of FIG. 2. Thus, it ispossible to obtain a DRAM having stable characteristics.

The description is given above of the preferred embodiments of thepresent invention. However, the present invention is not limited to thespecifically disclosed embodiments, and variations and modifications maybe made without departing from the scope of the claims.

According to the present invention, in a substrate for an electronicdevice including a semiconductor device whose characteristics may bedegraded by high temperature processing, by performing a hydrogensintering process with the use of microwave plasma having a highelectron density, it is possible to improve electric properties of thesemiconductor device while maintaining the substrate temperature to below. In addition, by propagating microwaves via a planar antenna, it ispossible to achieve low electron temperature and prevent damage on thesemiconductor device due to plasma damage. Further, since microwaves areemitted through propagation via the planar antenna, it is possible toprocess a large area in proportion to the area of the antenna. Thus,application to a substrate having a large area such as a wafer having adiameter of 300 mm and a TFT substrate having a large area becomes easy.

1. A substrate processing method that applies a hydrogen sinteringprocess to an electronic device substrate on which a semiconductordevice is already formed, the substrate processing method comprising thesteps of: forming an atmosphere comprising hydrogen radicals andhydrogen ions by exciting a processing gas including a noble gas andhydrogen into a plasma, and applying the hydrogen sintering process tothe electronic device substrate by exposing the electronic devicesubstrate to the hydrogen radicals and the hydrogen ions.
 2. The methodas claimed in claim 1, wherein the atmosphere including the hydrogenradicals and the hydrogen ions is selected from the group consisting ofhydrogen gas, heavy hydrogen gas, and mixtures thereof.
 3. The method asclaimed in claim 1, wherein the plasma is formed by microwaves.
 4. Themethod as claimed in claim 1, wherein the plasma is formed by emittingmicrowaves from a planar antenna.
 5. The method as claimed in claim 1,wherein the semiconductor device includes a MOSFET and a DRAM.
 6. Themethod as claimed in claim 1, wherein the substrate for the electronicdevice is selected from the group consisting of a Si substrate, a SiGesubstrate, and a glass substrate.
 7. The method as claimed in claim 5,wherein the MOSFET or DRAM includes one of a thermal oxide film and athermal nitride film as a gate insulation film.
 8. The method as claimedin claim 5, wherein a gate insulation film of the MOSFET is formed by aprocess selected from the group consisting of plasma oxidation, plasmanitriding, catalytic oxidation, catalytic nitriding, CVD, and PVD. 9.The method as claimed in claim 1, wherein the semiconductor deviceincludes a storage element using a high dielectric insulation film as aninterelectrode insulation film.
 10. The method as claimed in claim 1,wherein the hydrogen radicals and the hydrogen ions are formed at apressure of 13.3 to 267 Pa.
 11. A method of fabricating a semiconductordevice including a step of hydrogen sintering wherein an electronicdevice substrate is exposed to a plasma containing hydrogen, said methodcomprising the steps of: forming a gate insulation film on saidsubstrate; forming an electrode of polysilicon on said gate insulationfilm; and exposing said polysilicon electrode to an atmospherecontaining hydrogen radicals and hydrogen ions, said hydrogen radicalsand said hydrogen ions being formed by exciting a gas containing a noblegas and a hydrogen gas by plasma.
 12. The method as claimed in claim 11,wherein the atmosphere including the hydrogen radicals and the hydrogenions is selected from the group consisting of a hydrogen gas, a heavyhydrogen gas, and mixtures thereof.
 13. The method as claimed in claim11, wherein the plasma is formed by microwaves.
 14. The method asclaimed in claim 11, wherein the plasma is formed by emitting microwavesfrom a planar antenna.
 15. The method as claimed in claim 11, whereinthe semiconductor device includes a MOSFET and a DRAM.
 16. The method asclaimed in claim 11, wherein the substrate for the electronic device isselected from the group consisting of a Si substrate, a SiGe substrate,and a glass substrate.
 17. The method as claimed in claim 15, whereinthe MOSFET or DRAM includes one of a thermal oxide film and a thermalnitride film as a gate insulation film.
 18. The method as claimed inclaim 15, wherein a gate insulation film of the MOSFET is formed by aprocess selected from the group consisting of plasma oxidation, plasmanitriding, catalytic oxidation, catalytic nitriding, CVD, and PVD. 19.The method as claimed in claim 11, wherein the semiconductor deviceincludes a storage element using a high dielectric insulation film as aninterelectrode insulation film.
 20. The method as claimed in claim 11,wherein the hydrogen radical and the hydrogen ions are formed at apressure of 13.3 to 267 Pa.